Projection image display apparatus having a noise removal filter portion

ABSTRACT

In a projection image display apparatus, a noise removal filter portion  15  is separated from a power source unit body  14 . The separated noise removal filter portion  15  is provided in the vicinity of a side wall of a housing on which a power source inlet is provided, and of the power source unit body  14 , respectively. Specifically, the power source unit body  14  is provided along a side wall of a front face of the horizontally-long housing of the projection image display apparatus and the noise removal filter portion  15  is provided in a position opposed to the power source unit body  14  in a side wall of the back face. As a result, even when a light source lamp has a higher output, the projection image display apparatus can achieve reduced noise by an improved cooling capability and reduced cost enabled by an efficient Electro Magnetic Compatibility (EMC) measure and the like.

FIELD OF THE INVENTION

The present invention relates to a projection type image displayapparatus that has a noise removal filter portion for removing noisecoming via a power source inlet and that includes a power source unitfor supplying power to the respective parts including a light sourcelamp stored in a housing.

BACKGROUND OF THE INVENTION

A projection type image display apparatus such as a liquid crystalprojector uses, as a light source lamp, a high-pressure mercury lamp,metal halide lamp, and the like that are driven with a high voltage toemit light with high intensity. Thus, this projection type image displayapparatus includes a power source unit that includes a power sourcecircuit substrate including circuit components for supplying power tothe respective parts of the apparatus and a ballast circuit substratehaving thereon circuit components for supplying power exclusive to alight source lamp. This power source unit includes a noise removalfilter portion for removing noise coming via a power source inlet.

Japanese Patent Application Laid-Open Publication No. H10-186513discloses a projection type image display apparatus in which a noiseremoval filter portion is provided on a circuit substrate of a powersource unit.

A projection type image display apparatus such as a liquid crystalprojector has been required to realize higher intensity enabled by ahigher output of a light source lamp and reduction in cost and size ofthe apparatus. Such a light source lamp having a higher output requiresa power source unit to have a higher output.

In the case of the apparatus having a small output, there is no problemin the structure as in the above-described conventional technique inwhich a noise removal filter is provided on a circuit substrate of apower source unit. However, the larger output the apparatus requires,the larger the power source unit becomes, because the power source unitrequires a noise removal filter portion having a core (coil) that cannotbe downsized.

A power source unit having a larger size causes a fan for cooling thispower source unit to have a larger size or a higher output (rotatingspeed), resulting in a deteriorated cooling capability and increasednoise.

To prevent this, an arrangement may be considered in which the noiseremoval filter portion is separated from the apparatus. However, thisarrangement is disadvantageous in that noise easily enters a connectingwire to cause an increased use of a core, which raises a difficultproblem of an Electro Magnetic Compatibility (EMC) measure, therebycausing a higher cost.

SUMMARY OF THE INVENTION

The present invention has been made in order to solve the disadvantageas described above. It is an objective of the invention to provide aprojection type image display apparatus that includes a power sourceunit light that can realize, even when a light source lamp has a higheroutput, reduced noise enabled by an improved cooling capability and areduction in cost enabled by an EMC measure and the like.

In order to achieve the above objective, the present invention providesa projection type image display apparatus that has a noise removalfilter portion for removing noise coming via a power source inlet andthat includes a power source unit for supplying power to the respectiveparts including a light source lamp stored in a housing. The projectiontype image display apparatus modulates light emitted from the lightsource lamp based on an image signal to project the modulated imagelight in an expanded manner. The noise removal filter portion isseparated from the body of the power source unit. The separated noiseremoval filter portion is provided in the vicinity of a side wall of thehousing on which a power source inlet is provided and the body of thepower source unit, respectively.

According to this configuration, the noise removal filter portion isseparated from the body of the power source unit and the separated noiseremoval filter portion is provided in the vicinity of the side wall ofthe housing on which the power source inlet is provided, and of the bodyof the power source unit, respectively. This configuration can downsizethe body of the power source unit even when the light source lamp has ahigher output. Thus, reduced noise enabled by the improved coolingcapability can be achieved and the connecting wire can be the minimumlength to provide reduced cost enabled by an efficient EMC measure(e.g., reduced use of a core).

In this case, the noise removal filter portion is preferably provided inthe vicinity of the side wall of the housing on which the power sourceinlet is provided and the body of the power source unit, respectively.

By the above configuration, the side wall of the housing is free from apower source code. Thus, the effect of the above-described reduced costcan be obtained without deteriorating the usability of the side face ofthe housing.

The body of the power source unit is preferably provided along the sidewall of the front face of the horizontally-long housing and the noiseremoval filter portion is preferably provided in a position opposed tothe body of the power source unit in the side wall of the back face.

By the structure as described above, the connecting wire can have theminimum length even when the noise removal filter portion is providedalong the side wall of the back face. Thus, the effect of theabove-described reduced cost can be obtained without causing acomplicated arrangement of the respective components in the housing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a liquid crystal projector according toone embodiment of a projection type image display apparatus of thepresent invention, obliquely seen from above from the front side.

FIG. 2 is similarly a perspective view obliquely seen from above fromthe back side.

FIG. 3 is a perspective view in which an upper case in FIG. 1 isremoved.

FIG. 4 is a perspective view in which a main control substrate isfurther removed.

FIG. 5 is a perspective view in which an optical system is furtherremoved.

FIG. 6 is a top plan view of FIG. 5.

FIG. 7 is a view showing a configuration example of an optical system.

FIG. 8 is an enlarged view of principal parts showing a light sourcelamp cooling mechanism in the present embodiment, and is also aperspective view obliquely seen from above from the front side.

FIG. 9 is similarly a perspective view in which an upper half of a ductis removed and obliquely seen from above from the back side.

FIG. 10 is a perspective view in which a holder of the light source lampin FIG. 9 is removed.

FIG. 11 is a cross-sectional view of the principal parts seen from theback side.

FIG. 12 is an enlarged view of the principal parts showing an opticalpart cooling mechanism in the present embodiment, and is also aperspective view obliquely seen from above from the front side.

FIG. 13 is similarly a top plan view.

FIG. 14 is similarly a top plan view in which the optical parts areremoved.

FIG. 15 is similarly a back side view in which the lower half of theduct is removed.

FIG. 16 is a perspective view showing an exhaust fan unit constitutingan exhaust mechanism in the present invention.

FIG. 17 is similarly a perspective view showing the back side.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

One embodiment of the present invention will now be described below indetail with reference to the drawings.

FIG. 1 is a perspective view of a liquid crystal projector as oneembodiment of a projection type image display apparatus according to thepresent invention seen obliquely from above from the front side, FIG. 2is similarly a perspective view seen obliquely from above from the backside, FIG. 3 is a perspective view in which the upper case in FIG. 1 isremoved, FIG. 4 is a perspective view in which a main control substrateis further removed, FIG. 5 is a perspective view in which an opticalsystem is further removed, and FIG. 6 is a top plan view of FIG. 5.

As shown in FIGS. 1 and 2, a housing 2 forming an outer hull of thisliquid crystal projector 1 is compact, has a horizontally long thinrectangular shape, and consists of an upper case 2 a and a lower case 2b. When the upper case 2 a and a main control substrate 3 are removed,the interior thereof is displayed as shown in FIG. 4.

The left side seen from the front side of the front wall of the uppercase 2 a is formed with a projection window 5, from which a projectionlens 4 is exposed. The left side front portion of the upper surface ofthe upper case 2 a is formed with an operation window 6, from which anadjustable dial 4 a that adjusts zooming and focusing of the projectionlens 4 corresponding to the projection window 5 is exposed. The leftside back portion of the upper surface of the upper case 2 a is providedwith an operation display portion 7.

On the other hand, the right side wall of the lower case 2 b seen fromthe front side is formed with a plurality of slit-like exhaust holes 8.Both side corner portions of the bottom front portion of the lower case2 b are provided with leg portions 9 adjustable in height. On thebackside wall of the lower case 2 b, a power source inlet 10 connectedto a power source plug and an inlet and outlet terminal group 11 toconnect various types of input and output cables are exposed.

Inside the housing 2, as shown in FIGS. 3 and 4, looking from the frontside, the right side inner portion is disposed with a light source unit12, and at the same time, an optical system 13 reaching the projectionlens 4 from the light source unit 12 is disposed approximately inL-shape. In front of the light source unit 12, a power source main body14 stored with a power source circuit substrate mounted with the circuitparts to feed a power source to each portion of the apparatus and aballast circuit substrate mounted with circuit parts to feed the powersupply exclusively to the light source lamp is disposed, and in the backof the light source unit 12, a noise removal filter portion 15 to removethe noise infiltrating through the power source inlet 10 is disposed.

In the present embodiment, the noise removal filter portion 15 isseparated from the power source unit main body 14, and at the same time,the separated noise removal filter portion 15 is disposed to bepositioned as closely as possible to the housing back side wall providedwith the power source inlet 10 and the power source unit main body 14.Specifically, along the front side wall of the horizontally long house2, the power source unit main body 14 is disposed, and at the positionopposite to the power source unit main body 14 in the back side wall,the noise removal filter portion 15 mounted with a core (coil) 15 a andthe like on the substrate is disposed along the back side wall.

On the other hand, at the back side in an irradiating direction of thelight source unit 12, a suction fan 16 composed of a sirocco fan as afirst fan including the light source lamp cooling mechanism is disposed,and at the lateral side, an exhaust fan 17 composed of an axial fan as asecond fan constituting the light source lamp cooling mechanism isdisposed.

At the lateral side of the power source unit main body 14, an exhaustmechanism is provided. This exhaust mechanism is configured such that anexhaust fan 18 composed of the axial fan as a second exhaust fan ishorizontally disposed side by side with the exhaust fan 17.Incidentally, the exhaust fan 17 as the second fan constituting thelight source lamp cooling mechanism serves as the first exhaust fanconstituting the exhaust mechanism.

FIG. 7 is a view showing a configuration example of the optical system13. Incidentally, the optical system 13 is not limited to the one shownin FIG. 7 and the present invention can be applied to the apparatusprovided with various types of optical systems.

In FIG. 7, a white light from the light source lamp 19 passes through acondenser lens 20, a first integrator lens 21, a second integrator lens22, a polarizing beam splitter (PBS) 23, and a condenser lens 24 or thelike, and is irradiated at a first dichroic mirror 25.

The first integrator lens 21 and the second integrator lens 22 areconfigured by the fly-eye lenses composed of a plurality of lens cellsdisposed in a matrix array, and have functions to equalize theillumination distribution of the white light emitted from the lightsource lamp 19.

The polarizing beam splitter (PBS) 23 includes a polarizing separationmembrane and a phase retardation plate (½ wave plate). The polarizingseparation membrane allows, from among the light from the secondintegrator lens 22, for example, a P polarization to transmit, and an Spolarization slightly to change the light path and emit. The Ppolarization light having transmitted the polarization separationmembrane is converted into the S polarization by the phase retardationplate provided in the front side (light emitting side) thereof, and isemitted. That is, almost all the lights are aligned by the Spolarization.

The light having passed through the polarizing beam splitter 23 passesthrough a condenser lens 24, and reaches the first dichroic mirror 25.The first dichroic mirror 25 reflects a blue component only of thelight, and at the same time, has a function to allow red and greencomponents to pass through, and the passing light of the red and greencomponents reaches a second dichroic mirror 26. The second dichroicmirror 26 reflects a green component of the light, and at the same time,has a function to allow the red component to pass through. Consequently,the white light emitted from the light source lamp 19 is divided intothe blue light, the green light, and the red light by the first andsecond dichroic mirrors 25 and 26.

The blue light reflected by the first dichroic mirror 25 is reflected bya total reflection mirror 27, and the green light reflected by thesecond dichroic mirror 26 is as it is, and the red light having passedthe second dichroic mirror 26 is reflected by total reflection mirrors29 and 31 via relay les 28 and 30, and these are guided to an imagegenerating optical system 32, respectively.

The image generation optical system 32 is detachably disposed with aprism assembly part 35 (see FIG. 4) fitted with a liquid crystal panel34 r for the red color, a liquid crystal panel 34 g for the green color,a liquid crystal panel 34 b for the blue color, and the like,respectively, at the three lateral sides of a cube-shaped colorsynthesis prism 33. Between the color synthesis prism 33 and the liquidcrystal panel 34 r for the red color, an outgoing side polarizing plate36 r is disposed, and between the color synthesis prism 33 and theliquid crystal panel 34 g for the green color, an outgoing sidepolarizing plate 36 g and a fronting polarizing plate 37 g are disposed,and between the color synthesis prism 33 and the liquid crystal panel 34b for the blue color, an outgoing side polarizing plate 36 b and afronting polarizing plate 37 b are disposed. At the incident sides ofthree pieces of the liquid crystal panels 34 r, 34 g, and 34 b, incidentside polarizing plates 38 r, 38 g, and 38 b, and condenser lenses 39 r,39 g, and 39 b are disposed, respectively.

Consequently, the blue light reflected by the first dichroic mirror 25and the total reflection mirror 27 is guided to the condenser lens 39 bfor the blue color, and reaches the color synthesis prism 33 by passingthrough the incident side polarizing plate 38 b, the liquid crystalpanel 34 b for the blue color and the fronting polarizing plate 37 b,and the outgoing side polarizing plate 36 b. The green light reflectedby the second dichroic mirror 26 is guided to the condenser lens 39 gfor green color, and reaches the color synthesis prism 33 by passingthrough the incident side polarizing plate 38 g, the liquid crystalpanel 34 g for the green color and the fronting polarizing plate 37 g,and the outgoing side polarizing plate 36 g. Likewise, the red colorlight transmitting the first dichroic mirror 25 and the second dichroicmirror 26, and reflected by two pieces of the total reflection mirrors29 and 31, is guided to the condenser lens 39 r for the red color, andreaches the color synthesis prism 33 by passing through the incidentside polarizing plate 38 r, the liquid crystal panel 34 r for the redcolor and the outgoing side polarizing plate 36 r.

Three colors of image light guided by the color synthesis prism 33 issynthesized by this color synthesis prism 33, and the color image lightobtained by this synthesis passes through the projection lens 4, therebyto be enlargedly projected onto a frontward screen.

FIGS. 8 to 11 are enlarged views of principal parts showing the lightsource lamp cooling mechanism in the present embodiment. FIG. 8 is aperspective view of the front side seen obliquely from above, and FIG. 9is a perspective view of the back side seen obliquely from above inwhich an upper half of a duct is removed. FIG. 10 is a perspective viewin which a holder of the light source lamp in FIG. 9 is removed, andFIG. 11 is a cross-sectional view of the principal parts seen from theback side.

The light source lamp 19 of the present embodiment has an arc tube 191composed of a high-pressure mercury lamp, the metal-halide lamp, and thelike, and a reflector 192 disposed so as to cover this arc tube 19 andformed in the inner surface with a paraboloidal reflecting surface andopened in the front surface. This reflector 192, as shown in FIG. 10, isformed with a suction port 193 and an exhaust port 194 opposed to eachother on the front surface opening edge.

The light source lamp 19 thus configured is loaded on a lamp holder 195made of aluminum as shown in FIGS. 8 and 9. This aluminum lamp holder195 is configured to be provided with a heat-resisting glass plate 196blocking a front surface opening of the reflector 192, and at the sametime, formed with a ventilation wire netting 197 composed of a largenumber of small holes corresponding to the suction port 193 and theexhaust port 194 of the reflector 192, so that the fragment does not flyin all directions when the arc tube 191 is burst.

The conventional light source lamp cooling mechanism is disposed withthe fan and the discharge portion in consideration of the cooling onlyof the light source lamp, and therefore, even when the cooling of thelight source lamp is performed, by that much, the exhaust temperatureincreases. The projection type image display apparatus such as theliquid crystal projector has come to require a raised output of thelight source lamp and the miniaturization of the apparatus all together,and in the conventional art as explained above, even if the cooling ofthe light source lamp of a high output can be performed, the exhausttemperature exceeds a permissible zone of the user and increases toomuch, thereby making it difficult to achieve both the cooling of thelight source lamp and a reduction in the exhaust temperature. As itscountermeasure, when the output (the number of rotations) of the fan isincreased, the noise of the fan is increased.

Hence, the present embodiment includes, as a fan to cool the lightsource lamp 19, the suction fan (first fan) 16 having the innerdischarge port 161 sending the air through the suction port 193 formedin the reflector 192 inside the light source lamp 19 and the outerdischarge ports 162 and 163 sending the air to the outer surfaces of thereflector 192, and the exhaust fan (second fan) 17 exhausting an exhaustair around the light source lamp 19 to the outside through an exhausthole 8 formed in the side wall of the housing 2. The suction fan 16 iscomposed of the sirocco fan, and the exhaust fan 17 is composed of theaxial fan.

The outer discharge ports 162 and 163 of the suction fan 16 are formedby deviating from the outer surface center portion of the reflector 192of the light source lamp 19, and at the same time, the exhaust fan 17 isdisposed inclined such that its suction direction is directed toward theouter discharge ports 162 and 163 of the suction fan 16.

Each of the discharge ports 161, 162, and 163 circularly bends thedistal end of the duct 164 to the light source lamp 19 side and isformed on its distal end, the duct 164 extending to the lateral side ofthe light source lamp 19 from the suction fan 16 disposed at the lateralside in the irradiation direction of the light source lamp 19. An innerdischarge port 161 is formed by corresponding to a suction port 193formed in the reflector 192 of the light source lamp 19, while the outerdischarge ports 162 and 163 are formed above and below two pieces bydeviating vertically from the outside surface center portion of thereflector 192 of the light source lamp 19.

As explained above, the degree of deviating the outer discharge ports162 and 163 of the suction fan 16 from the outside surface centerportion and the degree of inclining the exhaust fan 17 such that itssuction direction is directed to the outer discharge ports 162 and 163of the suction fan 19 are set in consideration of the cooling of thelight source lamp 19 and the exhaust temperature.

By being thus configured, the interior of the light source lamp 19having the arc tube 191 reaching the highest temperature can beeffectively cooled by using the inner discharge port 161 of the suctionfan 16. The outer surface (including a neck portion 198 projected fromits back end) of the reflector 192 of the light source lamp 19, whichdoes not reach the temperature high enough as the interior of the lightsource lamp 19, can be suitably cooled by using the outer dischargeports 162 and 163 of the suction fan 16 formed by deviating from theouter surface center portion.

Since the exhaust fan 17 is disposed inclined such that its suctiondirection is directed to the outer discharge ports 162 and 163 of thesuction fan 16, the air from the outer discharge ports 162 and 163 ofthe suction fan 16 formed by deviating from the outer surface centerportion of the light source lamp 19 cools the outer surface of the lightsource lamp 19, and at the same time, a part of the air is directlysucked into the exhaust fan 17, and is mixed with the exhaust airincreased in temperature by having cooled the interior of the lightsource lamp 19, and is exhausted to the outside, thereby reducing theexhaust temperature.

Consequently, without increasing the outputs of the suction fan 16 andthe exhaust fan 17 so much, the cooling of the light source lamp 19 andthe reduction in the exhaust temperature can be both achieved, so thatthe noise can be also suppressed low.

Further, by forming the outer discharge ports 162 and 163 of the suctionfan 16 above and below two pieces by deviating from the outer surfacecenter portion of the light source lamp 19, the outer surface of thelight source lamp 19 can be approximately equally cooled.

The degree of deviating each of the discharge ports 161 and 162 of thesuction fan 16 from the outer surface center portion of the light sourcelamp 19 and the degree of inclining the exhaust fan 17 such that itssuction direction is directed toward the outer discharge ports 162 and163 of the suction fan 16 are set in consideration of the cooling of thelight source lamp 19 and the exhaust temperature, and therefore, thecooling of the light source lamp 19 and the reduction in exhausttemperature can be both flexibly achieved in conformity with the raisedoutput of the light source lamp 19, the miniaturization of theapparatus, and the like.

Further, each of the discharge ports 161, 162, and 163 of the suctionfan 16 is formed in the duct 164 extended from the suction fan 16 to thelight source lamp 19, so that a degree of freedom of the positioning ofthe suction fan 16 is improved.

Thus, according to the present embodiment, since the light source lampcooling mechanism as explained above is provided, so that, withoutincreasing the outputs of the fans 16 and 17 so much, the liquid crystalprojector 1 capable of achieving the cooling of the light source lamp 19and the reduction of the exhaust temperature as well as reducing thenoise can be realized.

FIGS. 12 to 15 are enlarged views of the principal parts showing anoptical part cooling mechanism in the present embodiment. FIG. 12 is aperspective view seen obliquely from above from the front side, FIG. 13is a top plan view, FIG. 14 is a top plan view in which optical partssuch as the liquid crystal panels and the like are removed, and FIG. 15is a back view in which the lower half of the duct is removed.

As explained earlier, heretofore, there has been known a device coolingthree pieces of liquid crystal panels corresponding to a red light, agreen light, and a blue light and polarizing plates disposed at theincident side and the outgoing side of each liquid crystal panel by oneset of the fan every color, that is, by a total of three sets of thefans.

Meantime, three pieces of the liquid crystal panels corresponding to thered light, the green light, and the blue light, and the polarizingplates and the like disposed at the incident side and the outgoing sideof each liquid crystal panel are different in temperature rise anddegree of ultraviolet deterioration every color, and therefore, therequired cooling amount is also different. Particularly, since the bluelight is close to the ultraviolet region, to avoid the ultravioletdeterioration, the required amount of cooling becomes large.

The projection type image display apparatus such as a liquid crystalprojector and the like has come to require the enhancement of luminanceby the raised output of the light source lamp, the miniaturization ofthe apparatus, and a reduced cost (miniaturization of the liquid crystalpanel and the like) all together, and the amount of light per unit areaof high luminance has come to be increased.

However, the conventional art that performs cooling by one set of thefan for each color has been unable to cope with the model whose amountof light per unit of high luminance has come to be increased. As acountermeasure, when the output of the fan (the number of rotations) isincreased, the noise of the fan is increased. Further, the cooling ofthe PBS needs to be also performed.

Hence, in the present embodiment, the incident side and the outgoingside of each of the liquid crystal panels 34 r, 34 g, and 34 b areformed with discharge ports r1 and r2, g1 and g2, and b1 and b2 todischarge the air from three sets of suction fans 41, 42, and 43 throughducts 411, 421, and 431. At the same time, the PBS 23 is formed with adischarge port p1 to discharge the air from the suction fan 43 throughthe duct 432. An incident side discharge port b1 and an outgoing sidedischarge port p2 of the liquid crystal panel 34 b corresponding to theblue color are formed with a duct so as to discharge the air from thesuction fans 43 and 41 which are different from each other.Incidentally, each of the suction fans 41 to 43 is composed of thesirocco fan.

That is, the duct is configured such that, by one set of the suction fan43, the air is sent to the incident side discharge port b1 of the liquidcrystal panel 34 b corresponding to the blue light and the dischargeport p1 of the PBS 23, and by the other two sets of the suction fans 41and 42, the air is sent to the incident side discharge ports r1 and g1of each of the liquid crystal panels 34 r and 34 g, to the outgoing sidedischarge port r2 and g2 corresponding to the red light and the greenlight, and to the outgoing side discharge port b2 of the liquid crystalpanel 34 b corresponding to the blue light.

To explain more specifically, the duct is configured such that, by oneset of the suction fan 42 from among two sets of the suction fans 41 and42, the air is sent to the incident side discharge port g1 and to theoutgoing side discharge port g2 of the liquid crystal panel 34 gcorresponding to the green light through the duct 421, and by the otherset of the suction fan 41, the air is sent to the incident sidedischarge port r1 and to the outgoing side discharge port r2 of theliquid crystal panel 34 r corresponding to the red light and theoutgoing side discharge port b2 of the liquid crystal panel 34 bcorresponding to the blue light by extending the duct 411.

By being thus configured, by three sets of the suction fans 41 to 43,the incident side and the outgoing side of each of the liquid crystalpanels 34 r, 34 g, and 34 b in addition to the PBS 23 can be cooled. Theincident side and the outgoing side of the blue light which is large inrequired cooling amount can be sufficiently cooled by using the suctionfans 43 and 41 which are different from each other. Consequently, evenwhen the amount of light per unit area of high luminance is increased,without increasing the output (the number of rotations) of the suctionfans 41 to 43 so much, the liquid crystal panels 34 r, 34 g, and 34 b,and the polarizing plates 36 r, 36 g, 36 b, 37 g, 37 b, 38 r, 38 g, and38 b, and the PBS 23 can be cooled by three sets of the suction fans 41to 43, thereby reducing the noise also.

Further, the duct is configured such that, by one set of the suction fan43, the air is sent to the incident side discharge portion b1 of theliquid crystal panel 34 b corresponding to the blue light and to thedischarge port p1 of the PBS 23, and by the other two sets of thesuction fans 41 and 42, the air is sent to the incident side dischargeports r1 and g1, to the outgoing side discharge ports r2 and g2 of eachof the liquid crystal panels 34 r and 34 g corresponding to the redlight and green light, and to the outgoing side discharge port b2 of theliquid crystal panel 34 b corresponding to the blue light, so that, inthe system disposed with the liquid crystal panel 34 b of the blue lightat the PBS 23 side similarly to the optical system 13 of the presentembodiment, by the shortest duct configuration, the above explainedeffect can be realized. Further, by the suction fan 41 for red lightthat increases least in temperature, the air can be sent to the outgoingside discharge port b2 of the liquid crystal panel 34 b corresponding tothe blue light. Incidentally, if the suction fan for the green lightthat increases most in temperature is not enough with one set of thesuction fan 42, the air may be sent from the suction fan 41 for redlight.

Similarly to the present embodiment, the duct is configured such that,by one set of the suction fan 42 from among the two sets of suction fans41 and 42, the air is sent to the incident side discharge port g1 and tothe outgoing side discharge port g2 of the liquid crystal panel 34 gcorresponding to the green light, and by another one set of the suctionfan 41, the air is sent to the incident side discharge port r1, to theoutgoing side discharge port r2 of the liquid crystal panel 34 rcorresponding to the red light, and to the outgoing side discharge portb2 of the liquid crystal panel 34 b corresponding to the blue light, sothat the above explained effect can be realized without the ductconfiguration becoming complicated.

Thus, according to the present embodiment, since the apparatus isprovided with the optical part cooling mechanism as explained above,even when the amount of light per unit area of high luminance isincreased, without increasing the output (the number of rotations) ofthe fan so much, the liquid crystal panel and the polarizing plate aswell as the PBS can be cooled by three sets of the fans, so that theliquid crystal projector 1 capable of reducing the noise can berealized.

Next, the power source unit of the present embodiment will be explained.

Heretofore, it has been common to mount a noise removal filter portionon the circuit substrate of the power source unit.

As explained above, the projection type image display apparatus such asa liquid crystal projector and the like has come to require theenhancement of luminance by the raised output of the light source lamp,the miniaturization of the apparatus, and a reduced cost all together,and because of the raised output of the light source lamp, the powersource unit has also come to require a large output.

However, in the case of the model having a small output, even when thenoise removal filter is mounted on the circuit substrate of the powersource unit similarly to the conventional art, this does not cause aproblem. However, when the output becomes large, a noise removal filterportion having a core (coil) incapable of being miniaturized becomeslarge, thereby upsizing the power source unit.

When the power source unit becomes large, the fan that cools this powersource unit also becomes large, and the output (the number of rotations)is required to be increased. This results in lowering of the coolingperformance and making the noise large. As its countermeasure, though itis conceivable to separate the noise removal filter portion and make itinto a separate type, a noise is liable to enter the connecting line,and because of the increased use of the core, the EMC (ElectroMagneticCompatibility) measure becomes formidable thereby inviting a high cost.

Hence, in the present embodiment, as explained above, the noise removalfilter portion 15 is separated from the power source unit main body 14,and at the same time, the separated noise removal filter portion 15 isdisposed to be positioned as closely as possible to the housing backside wall provided with the power source inlet 10 and the power unitmain body 14, respectively.

Specifically, along the front side wall of the horizontally long house2, the power source unit main body 14 is disposed, and at the positionopposed to the power source unit main body 14 in the back side wall, thenoise removal filter portion 15 is disposed along the back side wall.

By being thus configured, even when the output of the light source lamp19 becomes large, the power source unit main body 14 can beminiaturized, so that a reduction in the noise can be made possible bythe improvement of the cooling performance. In addition, the connectingline is minimized, so that a reduction in the cost is made possible bymaking the EMC measure (reduction in the use of the core and the like)more effective.

Further, by disposing the noise removal filter portion 15 close to thehousing back side wall provided with the power source inlet 10, a powersource cord is not brought to the lateral side of the housing 2, so thatthe above explained effect can be obtained with the usability of thelateral side of the housing 2 not harmed.

Further, the power source unit main body 14 is disposed along the frontside wall of the horizontally long house 2, and by disposing the noiseremoval filter portion 15 at the position opposed to the power sourceunit main body 14 in the back side wall, even when the noise removalfilter portion 15 is disposed along the back side wall, the connectingline can be made shortest, so that the above explained effect can beobtained without making the disposal configuration of each part insidethe housing 2 complicated.

Thus, according to the present embodiment, the power source unit asexplained above is provided, so that even when the output of the lightsource lamp 19 becomes large, the liquid crystal projector 1 capable ofreducing the cost by a reduction of the noise by improving the coolingperformance and making the EMC measure more effective can be realized.

Incidentally, in the present embodiment, since the housing 2 ishorizontally long, even when the power source unit main body 14 and thenoise removal filter portion 15 are arranged in parallel along the frontside wall and the back side wall, respectively, the connecting line canbe made shortest, while in the case of the housing vertically long frontto back, the disposition as explained above is unable to make theconnecting line shortest, and therefore, in this case, for example, ifthe noise removal filter is disposed front and back, then, it ispossible to dispose the noise removal filter portion close to thehousing back side wall and the power source unit main body,respectively.

Next, the exhaust mechanism in the present embodiment will be explained.

Heretofore, there has been known the exhaust mechanism placed with twosets of exhaust fans side by side close to the light source lamp, theexhaust fans exhausting the exhaust air to the outside from the lightsource lamp, the power source unit, and the like.

As explained above, while the projection type image display apparatussuch as the liquid crystal projector has come to require the raisedoutput of the light source lamp and the miniaturization of the apparatusall together. The exhaust air of high temperature from the high outputlight source lamp is exhausted, but a reduction in the exhausttemperature and a reduction in the noise of the exhaust fan have becomea key issue.

However, to achieve a reduction in noise of the side by side exhaustfans installed by the conventional art as explained above, a space needsto be left between the fan and the housing side wall, and this hindersthe miniaturization. To reduce the temperature of the exhaust air, it isconceivable to dispose each of the exhaust fans installed side by sideso as to be inclined in a V shape in the mutual exhausting direction sothat the exhaust air of high temperature from the light source lamp andthe exhaust air of the relatively low temperature from the power sourceunit and the like are mixed, but even in this case also, a spacetherefore is required, and the miniaturization is thus hindered.

Hence, in the present embodiment, as shown in FIGS. 3, 4, and the like,the first exhaust fan 17 which mainly exhausts the exhaust air from thelight source lamp 19 (light source lamp unit 12) to the outside and thesecond exhaust fan 18 which mainly exhausts the exhaust air from thepower source unit main body 14 to the outside are horizontally installedside by side, and at the same time, the second exhaust fan 18 side endportion in the first exhaust fan 17 is moved inward, and the firstexhaust fan 17 is disposed inclined such that its exhaust direction isdirected to the exhaust side of the second exhaust fan 18.

The first exhaust fan 17 is disposed inclined to a large number ofslit-like exhaust holes 8 formed in the housing side wall, and moreover,is disposed inclined such that the exhaust air from the exhaust holes 8are exhausted inclined obliquely forward.

The first exhaust fan 17 and the second exhaust fan 18, as shown inFIGS. 16 and 17, are fixed to a frame body 50 in advance and unitized soas to take on the above explained disposal configuration, and when thisexhaust fan unit 51 is fitted to the predetermined position of the lowercase 2 b of the housing 2, the above explained disposal configurationcan be easily realized. Incidentally, since the first exhaust fan 17sucks down the exhaust air of high temperature from the light sourcelamp 19, as shown in FIG. 17, the back side is configured to be coveredby a cover 52 with the center motor portion blocked and protect themotor portion from the exhaust air of high temperature from the lightsource lamp 19.

By being thus configured, the first exhaust fan 17 is inclined inward,so that the miniaturization is not hindered, and further, a space can beformed between the housing side wall and the first exhaust fan 17,thereby reducing the noise to a lower level. Further, the exhaust air ofhigh temperature from the light source lamp 19 and the exhaust air ofthe relative low temperature from the power source unit main body 14 aremixed, thereby reducing the temperature of the exhaust air.

Since the light source lamp is brought to a high temperature, and isdisposed spaced further apart from the exhaust fan than before, theabove explained configuration and effect can be easily realized.

Further, since the second exhaust fan 18 exhausts the exhaust air mainlyfrom the power source unit main body 14 to the outside, it can alsosimultaneously exhaust the exhaust air of the important power sourceunit main body 14, though not higher in temperature than the lightsource lamp 19.

Further, the first exhaust fan 17 which exhausts the exhaust air fromthe light source lamp 19 to the outside is disposed inclined to a largenumber of slit-like exhaust holes 8 formed in the housing side wall, sothat the air in high temperature from the light source lamp 19 isexhausted obliquely from a large number of slit-like exhaust holes 8,and by that much, the exhaust air becomes hard to be exhausted, therebyto be easily mixed with the exhaust air of the relatively lowtemperature from the second exhaust fan 18 with a result that theexhaust air temperature can be reduced much more than before.

Further, the first exhaust fan 17 which exhausts the exhaust air fromthe light source lamp 19 is disposed inclined so as to exhaust obliquelyfrontward the exhaust air from the exhaust holes 8 formed in the housingside wall, so that the exhaust air of high temperature can be preventedfrom being laterally blown out to an operator and the like.

Thus, according to the present embodiment, since the exhaust mechanismas explained above is provided, the liquid crystal projector 1 capableof reducing the noises of the exhaust fans 17 and 18 and lowing theexhaust temperature, while achieving down-sizing can be realized.

Incidentally, in the present embodiment, though the first exhaust fan 17has been inclined, if an extra room available inside space-wise, evenwhen the second exhaust fan 18 is conversely inclined similarly to thefirst exhaust fan, a fixed effect can be expected.

1. A projection image display apparatus having a noise removal filterportion for removing noise coming via a power source inlet andcomprising a power source unit for supplying power to the respectiveparts including a light source lamp stored in a housing, which modulateslight emitted from the light source lamp based on an image signal toproject the modulated image light in an expanded manner, wherein thenoise removal filter portion is provided within the housing is separatedfrom the body of the power source unit and the separated noise removalfilter portion is provided in the vicinity of a side wall of the housingon which the power source inlet is provided, and of the body of thepower source unit, respectively.
 2. The projection image displayapparatus according to claim 1, wherein the noise removal filter portionis provided in the vicinity of a side wall of a back face of the housingon which the power source inlet is provided, and of the body of thepower source unit, respectively.
 3. The projection image displayapparatus according to claim 2, wherein the body of the power sourceunit is provided along a side wall of a front face of thehorizontally-long housing and the noise removal filter portion isprovided in a position opposed to the body of the power source unit inthe side wall of the back face.